Clean up reading and writing in init.
This isn't particularly useful in and of itself, but it does introduce the
first (trivial) unit test, improves the documentation (including details
about how to debug init crashes), and made me aware of how unpleasant the
existing parser is.
I also fixed a bug in passing --- unless you thought the "peboot" and "pm"
commands were features...
Bug: 19217569
Change-Id: I6ab76129a543ce3ed3dab52ef2c638009874c3de
diff --git a/init/util.cpp b/init/util.cpp
index 84fe536..3dddb15 100644
--- a/init/util.cpp
+++ b/init/util.cpp
@@ -35,6 +35,8 @@
/* for ANDROID_SOCKET_* */
#include <cutils/sockets.h>
+#include <utils/file.h>
+
#include <private/android_filesystem_config.h>
#include "init.h"
@@ -146,48 +148,42 @@
return -1;
}
-/* reads a file, making sure it is terminated with \n \0 */
-char *read_file(const char *fn, unsigned *_sz)
-{
- char *data = NULL;
- int sz;
- int fd;
+bool read_file(const char* path, std::string* content) {
+ content->clear();
+
+ int fd = TEMP_FAILURE_RETRY(open(path, O_RDONLY|O_NOFOLLOW|O_CLOEXEC));
+ if (fd == -1) {
+ return false;
+ }
+
+ // For security reasons, disallow world-writable
+ // or group-writable files.
struct stat sb;
-
- data = 0;
- fd = open(fn, O_RDONLY|O_CLOEXEC);
- if(fd < 0) return 0;
-
- // for security reasons, disallow world-writable
- // or group-writable files
- if (fstat(fd, &sb) < 0) {
- ERROR("fstat failed for '%s'\n", fn);
- goto oops;
+ if (fstat(fd, &sb) == -1) {
+ ERROR("fstat failed for '%s': %s\n", path, strerror(errno));
+ return false;
}
if ((sb.st_mode & (S_IWGRP | S_IWOTH)) != 0) {
- ERROR("skipping insecure file '%s'\n", fn);
- goto oops;
+ ERROR("skipping insecure file '%s'\n", path);
+ return false;
}
- sz = lseek(fd, 0, SEEK_END);
- if(sz < 0) goto oops;
+ bool okay = android::ReadFdToString(fd, content);
+ TEMP_FAILURE_RETRY(close(fd));
+ if (okay) {
+ content->append("\n", 1);
+ }
+ return okay;
+}
- if(lseek(fd, 0, SEEK_SET) != 0) goto oops;
-
- data = (char*) malloc(sz + 2);
- if(data == 0) goto oops;
-
- if(read(fd, data, sz) != sz) goto oops;
- close(fd);
- data[sz] = '\n';
- data[sz+1] = 0;
- if(_sz) *_sz = sz;
- return data;
-
-oops:
- close(fd);
- free(data);
- return 0;
+int write_file(const char* path, const char* content) {
+ int fd = TEMP_FAILURE_RETRY(open(path, O_WRONLY|O_CREAT|O_NOFOLLOW|O_CLOEXEC, 0600));
+ if (fd == -1) {
+ return -errno;
+ }
+ int result = android::WriteStringToFd(content, fd) ? 0 : -errno;
+ TEMP_FAILURE_RETRY(close(fd));
+ return result;
}
#define MAX_MTD_PARTITIONS 16